Apparatus for heat treatment of tissue

ABSTRACT

A device for heat treatment of body tissue, including heating means ( 10 ) for local heating of the body tissue, and temperature sensing means ( 11 ) for sensing the tissue temperature, said heating means being enclosed in a catheter ( 12 ). A first temperature sensing means ( 11 ) is connected to a first carrier ( 13 ), which is made to be advanced through a first opening in catheter ( 12 ), and said first carrier ( 13 ) is equipped with a pointed tip for insertion into such body tissue that is to be heat-treated.

TECHNICAL FIELD OF THE INVENTION

The invention concerns a device for heat treatment of body tissue inaccordance with patent claim 1.

Certain conditions of illness with unnatural growth of body tissue aresuccessfully managed by the use of heat treatment. The tissue is heatedto such an extent that the tissue dies. Certain types of cancer andhyperplasia in the prostate gland are examples of such conditions ofillness. During treatment certain parts of the tissue are to be treatedwhereas others must or should be protected.

STATE OF THE ART

Various devices may be used for the purpose of producing heat. Laser aswell as microwave and RF antennas are commonly used. Because the volumeof the tissue to be treated varies, as does the heat-absorption qualityof both this first-mentioned tissue and adjacent tissue, which is not tobe treated, it is appropriate that continuous control takes place duringtreatment.

It is commonplace that the means of heating comprises some kind of atemperature sensor, which is provided on the heat-producing element tosense the temperature of an adjacent tissue. A drawback of this designis that the temperature sensor lends information that is more pertinentto the temperature of the element than to that of the tissue.

An example of this type of heating device is shown and described in EP 0370 890. The device comprises a microwave antenna enclosed in acatheter. The antenna is designed to emit electromagnetic energy to thetissue surrounding the antenna. The catheter is also equipped withcooling channels for cooling of the tissue closest to the catheter.There is provided a temperature transducer in the catheter to sense thetemperature of the catheter. The temperature sensed therefore does notagree with that of the tissue to be treated.

Another example of this is to be found in U.S. Pat. No. 5,366,490.According to that patent specification, previously known heating devicespresent multiple drawbacks. The most critical of these drawbacks is thatheating takes place in a diffusely defined area or volume. In particularsystems comprising a microwave antenna in a catheter, it is specified,lead to great risks and worse treatment outcome because the area oftreatment is not narrowly defined.

According to U.S. Pat. No. 5,366,490, it is therefore suggested that themeans of treatment is provided in a needle which is advanceable so as toexit a catheter. The catheter and then the needle are controlled veryaccurately in place with the aid of an ultra sound device, which duringthe entire treatment continuously monitors the area of treatment.Control of the needle must be very precise since treatment efficiency islocally very high in the vicinity of the needle. The treatment is asurgical one. There are high demands on the person who carries out thetreatment and on the surgical equipment required.

SUMMARY OF THE INVENTION

It is an objective of the present invention, when it comes toconventional types of heat treatment devices, to provide a device whicheliminates the drawbacks of diffusely working heating means that areequipped with temperature sensors. The objective is achieved by thefeatures indicated in claim 1. According to the present invention,registration of relevant temperature data from the body tissue isreadily made possible. Treatment made possible through the deviceaccording to the invention may take place in an outpatient settingwithout the requirement of surgical staff and equipment or operationrooms.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view partially in a cross-section of one embodiment ofthe device according to the invention.

FIG. 2 is a cross-sectional view from line II—II of FIG. 1.

FIG. 3 is a principal longitudinal view of a practical embodiment of adevice according to the invention.

FIG. 4 is a cross-sectional view, from line IV—IV of FIG. 3, of analternate embodiment of a device according to the invention,

FIG. 5 is a principal longitudinal view of an alternate, practicalembodiment of a device according to the invention, during assembly.

FIG. 6 is a cross-sectional view, from line VI—VI in FIG. 7, of yetanother alternate embodiment of a device according to the invention, and

FIG. 7 is a longitudinal partial view, taken from line VII—VII, of thedevice of FIG. 8.

DESCRIPTION OF THE INVENTION

In the embodiment schematically shown in FIG. 1, a catheter 12 has beeninserted into the urethra in such a manner that a tip or apex 16 ofcatheter 12 has entered into the urine bladder 17. Prior to start of thetreatment, a balloon 18 connected to catheter 12 is expanded inside theurine bladder. Unintentional extraction of the catheter 12 is therebyprevented. An external sphincter 20 schematically indicates suchsurrounding tissue which is not to undergo treatment.

Catheter 12 comprises means 10 for heating tissue in the prostate gland19. In a preferred embodiment, the heating device 10 comprises anantenna for emission of electromagnetic energy. The antenna usuallyoperates within the frequency range of 1 MHz-5000 MHz. In otherembodiments, the heating device 10 comprises receptacles containing, aheated liquid. The heating may take place through circulation of theheated liquid through catheter 12, or through some form of a heatingelement in a direct connection to the receptacle. It is also possible tohave the heating device 10 abut either directly to the tissue orindirectly via an intermediary device. The intermediary device may be sodesigned that it expands during heating, thus allowing for an improvedabutment against the tissue, and improved heat transmission as well.

In yet other embodiments, the heating device 10 may comprise one orseveral smaller radio frequency electrodes provided externally on thecatheter. A larger electrode interacts with the catheter electrode insuch a way that it is heated by the transmitted radio energy.

An active portion of the heating device 10 is located in the prostategland 19. Supply of the energy, which is to be emitted to the tissue,preferably occurs in channels in catheter 12. Below, these will bedescribed in more detail with reference to FIG. 2.

In the course of an ongoing treatment the tissue is heated. Heatingshould occur within certain temperature intervals for the sake ofoptimal treatment results. If the temperature is too elevated,unnecessary severe damage is inflicted on the tissue. If the temperatureis too low, on the other hand, the desired treatment result is notachieved. In order to be directly able to register temperature increasein the tissue to be treated a first temperature sensing means 11 isconnected to a first carrier 13. Carrier 13 is run through a channel incatheter 12 and is provided so as to be advanced through an opening incatheter 12. Preferably, there is provided a guide for carrier 13 in theopening of the catheter, so as to guide carrier 13 out and into thetissue at a desired angle relative to catheter 12. Carrier 13 may alsorun in a tubing in the catheter. The guide includes a sloping orinclined portion, against which the carrier 13 can be brought and, thus,be angled out and, upon further advancement, moved away from thecatheter. The carrier 13 is constructed of a relatively stiff material,thus facilitating penetration and insertion into the tissue.

Either carrier 13 or temperature sensing means 11 is equipped with atip, which allows for a more simplified insertion into the tissue.Temperature sensing means 11 may be either conventionally designed as aresistive transducer or a semi-conductor. The cable drawing required forsuch transducers is preferably carried out through catheter 12. If anoptical type of transducer is used, a fiber optic conductor is providedthrough catheter 12.

Advancement of the temperature sensing means 11 or its carrier 13 out ofcatheter 12 is controlled by control means from the exterior of thecatheter outside of the body. This should preferably occur in a welldefined way so that insertion into the tissue is implemented down to thedesired depth. In a simple design, carrier 13 is made as a stiff tubeending in a tip and is provided to extend through a channel in catheter12. Temperature sensing means 11 is provided at one end of carrier 13.At the other end, carrier 13 is equipped with a handle. The channel andcarrier 13, which is contained in the channel, are given such dimensionsand such a bending resistance that the degree of advancement becomeswell defined in relation to the longitudinal advancement of the carrier.The advancement by maneuvering of the handle and carrier is limited by astop or some arresting means so as to avoid the risk of the temperaturesensing means 11 passing beyond the desired area of temperature sensing.

By continuously sensing of the temperature in the tissue being treated,it is possible to accurately control supplied power and the end result.Thus, the risk of undesired damage to the tissue is significantlydiminished.

In order to further lessen the risk of damage, and more specifically insuch surrounding tissue which shall not be reached through treatment, asecond temperature sensing means 14 is connected to a second carrier 15.This second carrier 15 is designed to be advanced through and out ofcatheter 12 at a certain distance from the first carrier 13 in thelongitudinal direction of the catheter 12. The distance is determined bythe size of the treatment area and is ample enough to allow temperaturesensing means 14, in its forwardly advanced state, to penetrate intosuch a tissue which should not be damaged during treatment. In the shownembodiment the second temperature sensing means 14 measures thetemperature in the sphincter 20.

The cross-section view of FIG. 2 shows an example of how catheter 12 maybe designed. The heating device 10 and its conductor for energy supplyare contained in a centrally provided, first channel or tube 21. Tube 21is surrounded by two radially displaced, communicating cavities 22, 23.Through these cavities there is distributed a cooling medium or coolantfor cooling the tissue in direct contiguity to the heating device 10 insuch applications for which heat treatment is directed towards thetissue at a certain radial distance from the heating device 10 andcatheter 12. This is specifically applicable in cases when the heatingdevice 10 includes an antenna.

The cooling medium is mainly used to avoid heating of tissue surroundingthe catheter on its way to the treatment area, and which would be due toheat loss or similar from the conductor of the heating device 10.

Different portions of the catheter periphery are joined by two portions24, 25, in which there are provided elongate channels 26 to allow forinflation and deflation of balloon 18. Portions 24, 25 merge into thecentral tube 21.

In the practical embodiment of the device according to the invention,shown in FIG. 3, a tubing 27 made of Teflon or a similar material isprovided external to the catheter. Tubing 27 is connected to a sleeve 28mounted on catheter 12. Sleeve 28, in a portion outside of the orificeof tubing 27, is provided with an inclined portion 29. Preferably thesleeve is arranged with relation to the heating device 10 in such a waythat the sleeve, in its operative mode, is located in the periphery oroutside of the working area of heating device 10.

The annular sleeve member 20 28also has a stiffening effect, whichprevents undesirable downward bending of catheter 12 in conjunction withforward push advancement of carrier 13. The length of annular member 2028is adjusted to retain the suppleness and pliability of catheter 12.

Carrier 13, which is equipped with one or several temperature sensingmeans 11; 14, extends through tubing 27. Carrier 13 is rigid and has apointed end. When the carrier is pushed in and passed through tubing 27and reaching the inclined portion 29, which is preferably composed of arelatively hard material, carrier 13 is bent into a certain angleprojecting out from the longitudinal direction of catheter 12. Anadvantageous angle has to be at least approximately 20°. A preferredangle is 30°. During continued insertion of carrier 13, its pointed endtip will penetrate the tissue outside of sleeve 28, and will penetratefurther into the tissue as forward advancement continues. Selection ofmaterials for carrier 13 and tubing 27 is done so that friction betweenthem becomes suitably low.

As shown by FIG. 3, carrier 13 is equipped with several temperaturetransducers. These are arranged with a distance between them. A firsttemperature transducer 11 is provided at the pointed end tip of carrier13, and a second temperature transducer 14 is provided at a distancefrom the pointed end tip corresponding to a normal distance ofadvancement by push of the carrier out of sleeve 28. Thereby this secondtemperature transducer 14 will be located in the periphery or outside ofthe area of treatment. There is provided an additional temperaturetransducer 11′ between the two abovementioned temperature transducers11;14. In the normal operative mode this third temperature transducer11′ is located in the middle of the area of treatment.

In the embodiment as per FIGS. 4 and 5, tubing 27 is arranged to runinternally in catheter 12, most preferably within one of the channels 22or 23. Tubing 27 at one end is attached to an end piece, which likesleeve 28 comprises a sloping or inclined portion 29. End piece 30constitutes part of catheter 12, or is joined to catheter 12 so that theinclined portion 29 is located outside of an opening 31 made in catheter12. Tubing 27 runs through this opening 31. During manufacture of acatheter according to this embodiment it is suitable that tubing 27 isled into the opening 31 from the outside and then led back through thecatheter and out through an open end of the catheter. There isindication about such a procedure in FIG. 5, wherein end piece 30 hasnot yet been fastened to the exterior of catheter 12. Some materialsused for tubing 27 must have a mechanical connection, for instanceclamping, of the tubing against or onto end piece 30. Upon connection,tubing 27 should exhibit such a direction that a carrier, which ispushed out through the orifice of tubing 27, hits the inclined portion29 and is outwardly directed at a desirable angle.

The end piece 30 and the orifice of tubing 27 are preferably covered bya diaphragm or a membrane. This allows for simple sterilization andcleaning of catheter 12 prior to usage. Upon insertion of catheter 12into the treatment position, the diaphragm will be penetrated by carrier13 in conjunction with the forward advancement of the carrier andtemperature sensing means. In one embodiment, end piece 30 is providedas a supple plate, which covers part of the circumference of catheter12.

For some applications it may prove insufficient with two temperaturesensing means. Several elongate cavities for carriers and relatedsensing means will then be provided in the catheter. The heating devicecould also be provided in several separated elements. These could bearranged in multiple tubes or channels as well.

In the embodiment as per FIG. 6, tubing 27 is provided in a specialcavity of catheter 12. Tubing 27 runs through virtually the entirecatheter 12. A peg 32 (see FIG. 7) is inserted into tubing 27 from theend facing the tip 16. Peg 32 is an end member in the tubing and isprovided with an oblique, pointed end face 33, which has the samefunction as the inclined portion 29 in the embodiments described above.If stiffening of catheter 12 is required in this embodiment, one orseveral stiffening members 34 are preferably provided in catheter 12, sothat catheter 12 obtains completely smooth exterior. Advantageously, thestiffening members 34 are arranged in channels 22 and 23, as shown inFIG. 6.

In FIG. 7, only part of catheter 12 is shown as designed in accordancewith FIG. 6. Carrier 13 has been introduced into tubing 27 unto aposition in which the pointed end tip engages the pointed end face ofpeg 32. As in the embodiments described above, carrier 13 upon furtherinsertion of tubing 27 will be forced to deviate from an axial directionand adopt a deflected angle determined by the inclination of the slopingportion 29, which in this embodiment is represented by the pointed endface of peg 32. Carrier 13, in the shown embodiment, penetrates both thetubing 27 and the wall of catheter 12. In other embodiments, catheter 12may be provided with a weakened portion in the area which is to bepenetrated. It is also possible to make an opening, in advance, incatheter 12 and/or in tubing 27. The opening is preferably covered by amembrane or similar during insertion into the urethra or equivalent.

The increased resistance, which appears during deflection against theinclined portion 29 or pointed end face 33, can be used to define astarting point from which to determine the depth of insertion into thetissue, of carrier 13 with its pointed tip and temperature sensing means11. This depth is also determined by the deflection angle. The signalsgenerated at least by the first temperature sensing means 11 areconducted to an indicator unit, by means of which the attending staffcan continuously assess the treatment. Preferably, the signals are alsosent to a control unit not detailed herein, and which controls supply ofpower to the heating device 10. In the case of multiple temperaturesensing means being used, it would be preferable to connect them to theindicator unit and/or control unit.

I claim:
 1. A device for heat treatment of prostate tissue comprising:heating means for local heating of the prostate tissue; a urologicalcatheter enclosing said heating means; and a first temperature sensingmeans connected to a first carrier, said first carrier for sensing thetemperature of the prostate tissue being movable through radially andout a wall of said catheter and said first carrier having a first endforming a first pointed tip, wherein said first pointed tip beingadapted for insertion into the prostate tissue that is to be heattreated and that is located radially of said urological catheter.
 2. Thedevice according to claim 1 further comprising: A device for heattreatment of prostate tissue comprising: heating means for local heatingof the prostate tissue; a urological catheter with a longitudinal axisand completely enclosing said heating means; a first temperature sensingmeans connected to a first carrier, said first carrier for sensing thetemperature of the prostate tissue, said first carrier being movablethrough and radially out a wall of said catheter relative to thelongitudinal axis, and said first carrier having a first end forming afirst pointed tip, wherein said first pointed tip being adapted forinsertion into the prostate tissue that is to be heat treated and thatis located radially of said catheter upon movement of said first carrierthrough and out the wall of said catheter; and a second temperaturesensing means connected to a second carrier, said second carrier forsensing the temperature of prostate tissue which is to be excluded fromsaid heat treatment, said second carrier being movable through and outof said catheter catheter, and said second carrier having a first endformed with a second pointed tip, wherein said second tip being adaptedfor insertion into prostate tissue which is to be excluded from saidheat treatment upon movement of said second carrier through and out ofsaid catheter.
 3. The device according to claim 1, wherein said firstcarrier is contained in cavities in said catheter.
 4. The deviceaccording to claim 1 2wherein said first carrier is contained in atubing located on said catheter.
 5. The device according to claim 4wherein said tubing debouches into an end piece, said end piece havingan inclined portion for angulation of said first carrier.
 6. The deviceaccording to claim 5 wherein said end piece is provided externally onsaid catheter and said end piece is made of a material that is morerigid than said catheter so as to avoid undesired kinking of saidcatheter.
 7. The device according to claim 5 wherein said end piece isprovided internally in said catheter.
 8. The device according to claim 7further comprising: at least one stiffening member positioned internallyin said catheter.
 9. The device according to claim 1 2wherein saidheating means comprises at least one microwave antenna for delivery ofenergy to the body tissue.
 10. The device according to claim 9 furthercomprising: at least one heat-absorbing means in the vicinity of saidmicrowave antenna for dissipation of heat from prostate tissue closestto said antenna.
 11. The device according to claim 10 wherein said atleast one heat-absorbing means comprises channels which extend throughsaid catheter and to contain a cooling medium being distributed throughsaid channels.
 12. The device according to claim 11 wherein stiffeningmeans is positioned in said channels in said catheter.
 13. The deviceaccording to claim 1 2wherein at least one heat-absorbing means isprovided for dissipation of heat from the prostate tissue closes to asupply lead connected to said heating means.
 14. The device according toclaim 1 2wherein said first and second temperature sensing means isareconnected to a control unit, said control unit controlling the power ofsaid heating means.
 15. A method for heat treatment of prostate tissuesurrounding a urethra that extends from a distal bladder to a proximalexterior of a body, comprising the steps of: extending a catheter intothe urethra from the exterior of the body into the bladder; locallocallyheating of the prostate tissue with at least one heating means, saidheating means being which is enclosed in a said catheter; continuouslysensing of the temperature of the locally-heated prostate tissuetemperature at a plurality of different radially outward spacedlocations relative to the urethra with a temperature sensing means; andadvancing said temperature sensing means which is connected with a firstcarrier through and radially out of said catheter and into the prostatetissue; which is to be treated and is located radially external to saidcatheter for and continuous control continuously controlling thetemperature of the locally-heated prostate tissue based on thetemperature sensed at the plurality of different locations.
 16. Thedevice according to claim 2, wherein said first and second carriers arecontained in at least one cavity which extends longitudinally along saidcatheter.
 17. The device according to claim 16 wherein said firstcarrier is contained in a tubing which is located in one said cavity,and said second carrier is contained in a tubing which is located in onesaid cavity.
 18. The device according to claim 2 wherein said heatingmeans comprises a comprises a receptacle within the catheter forcontaining heated liquid.
 19. The device according to claim 2 whereinsaid heating means comprises an intermediary device which expands intoabutment against the urethra.
 20. A method as defined in claim 15further comprising: using separate temperature sensors positioned atspaced apart positions along a distal end portion of the carrier tosense each of the plurality of temperatures by a separate temperaturesensor.
 21. A method as defined in claim 20 further comprising: sensinga first temperature of the locally-heated prostate tissue at arelatively greater radial outward location through which the distal endportion of the carrier has penetrated; and sensing a second temperatureof the locally-heated prostate tissue at a relatively lesser radialoutward location through which the distal end portion of the carrier haspenetrated.
 22. A method as defined in claim 21 further comprising:sensing a third temperature of the locally-heated prostate tissue at arelatively intermediate location through which the distal end portion ofthe carrier has penetrated, the intermediate location existing betweenthe locations where the first and second temperatures are sensed.
 23. Amethod as defined in claim 20 further comprising: locally heating theprostate tissue in an area of heat treatment; penetrating the distal endportion of the carrier into the prostate tissue at a periphery of thearea of heat treatment as well as within the area of heat treatment;sensing the plurality of temperatures of the locally-heated prostatetissue within the area of heat treatment; and additionally sensing thetemperature of the prostate tissue at the periphery of the area of heattreatment.
 24. A method as defined in claim 23 further comprising:sensing the temperature outside of the periphery of the area of heattreatment.
 25. A method as defined in claim 23 further comprising:penetrating the prostate tissue with the distal end portion of thecarrier in a longitudinal direction as well as the radially outwarddirection relative to the urethra; and sensing the plurality oftemperatures at a plurality of different radially spaced andlongitudinally separated locations within the area of heat treatment.26. A method as defined in claim 25 further comprising: penetrating theprostate tissue with the distal end portion of the carrier in thelongitudinal direction toward the bladder.
 27. A method as defined inclaim 26 further comprising: penetrating the prostate tissue with thedistal end portion of the carrier at an angle of at least 20 degreesrelative to the catheter.
 28. A method as defined in claim 26 furthercomprising: penetrating the prostate tissue with the distal end portionof the carrier at an angle of approximately 30 degrees relative to thecatheter.
 29. A method as defined in claim 15 further comprising:emitting energy from an antenna within the catheter to locally heat theprostate tissue.
 30. A method as defined in claim 15 further comprising:conducting heat from a heated liquid within the catheter to locally heatthe prostate tissue.
 31. A method as defined in claim 15 furthercomprising: locally heating the prostate tissue by delivering energyfrom a heating device positioned within the catheter.
 32. A method asdefined in claim 15 further comprising: expanding an intermediary deviceinto abutment against the urethra while locally heating the prostatetissue.
 33. A method as defined in claim 15 further comprising: pushingthe carrier longitudinally at the exterior of the body to advance saidtemperature sensing means into the prostate tissue.
 34. A method asdefined in claim 15 further comprising: retaining the catheter in theurethra relative to the bladder by expanding a balloon at the distal endof the catheter within the bladder and by penetrating the prostatetissue with a distal end portion of the carrier in a longitudinaldirection toward the bladder.
 35. A method as defined in claim 15further comprising: continuing the penetration of a distal end portionof the carrier into the prostate tissue in substantially the directioninitiated upon advancing the carrier by utilizing substantially only aninherent stiffness characteristic of the distal end portion of thecarrier.
 36. A catheter for use during heat treatment of prostate tissueof a living body, the prostate tissue surrounding a urethra that extendsfrom a distal bladder to a proximal exterior of the body, the cathetercomprising: a length sufficient to extend through the urethra from theexterior of the body and into the bladder; an expandable balloonpositioned at a distal end of the catheter to be expanded within thebladder to retain the catheter in the urethra relative to the bladder; achannel extending from the exterior of the body along the catheter andterminating at a distal end located at a predetermined position spacedproximally from the expandable balloon; a carrier extending from theexterior of the body through the channel and having a distal end portionto be advanced out of the terminating distal end of the channel and intothe prostate tissue by applying advancement force to the carrier at theexterior of the body; a deflecting element located at the terminatingdistal end of the channel to deflect the distal end portion of thecarrier into the prostate tissue in a direction radially outwardrelative the catheter when the balloon retains the catheter relative tothe bladder and upon advancement of the carrier out of the terminatingdistal end of the channel; and a plurality of temperature sensorspositioned in a spaced apart relationship along the distal end of thecarrier to determine the temperature of the prostate tissue at aplurality of different radially outward spaced locations into which thedistal end of the carrier has penetrated.
 37. A catheter as defined inclaim 36 wherein: a first one of the temperature sensors is positioneddistally at the distal end portion of the carrier; and the carrier hasstiffness characteristics which advance the distal end portion into theprostate tissue to locate the first temperature sensor at a maximumradial outward location upon advancement of the carrier.
 38. A catheteras defined in claim 37 wherein: a second one of the temperature sensorsis positioned proximally from the distal end portion of the carrier tobe located in the prostate tissue at a minimum radial outward location.39. A catheter as defined in claim 38 wherein: a third one of thetemperature sensors is positioned between the first and secondtemperature sensors on the distal end portion of the carrier to belocated in the prostate tissue at a lesser radial outward location thanthe first temperature sensor and a greater radial outward location thanthe second temperature sensor.
 40. A catheter as defined in claim 36further comprising: a heating device in the catheter which is spacedrelative to the expandable balloon at a predetermined position todeliver heat to the prostate tissue in an area of heat treatmentsurrounding the urethra when the catheter is retained relative to thebladder; and at least two temperature sensors are located within thearea of heat treatment.
 41. A catheter as defined in claim 40 wherein:the two temperature sensors are located within the area of heattreatment at different radially outward spaced locations relative to theurethra and at different locations longitudinally along the urethra. 42.A catheter as defined in claim 41 wherein: at least one temperaturesensor is located at a periphery of the area of heat treatment.
 43. Acatheter as defined in claim 42 wherein: the temperature sensor locatedat the periphery of the area of heat treatment is outside of the area ofheat treatment.
 44. A catheter as defined in claim 41 wherein: a firstone of the temperature sensors is located at a relatively greater radialoutward spaced location relative to the urethra; a second one of thetemperature sensors is located within the area of heat treatment at arelative middle radial outward spaced location relative to the urethra;and a third temperature sensor is located at a periphery the area ofheat treatment.
 45. A catheter as defined in claim 44 wherein: the thirdtemperature sensor is located outside of the area of heat treatment. 46.A catheter as defined in claim 40 wherein: the deflecting elementdeflects the distal end portion of the carrier to penetrate into theprostate tissue in a longitudinal direction as well as the radiallyoutward direction.
 47. A catheter as defined in claim 46 wherein: thedeflecting element comprises a curved distal portion of the channel. 48.A catheter as defined in claim 46 wherein: the deflecting elementcomprises an inclined member positioned at the distal portion of thechannel to deflect the distal end portion of the carrier into thelongitudinal and radial outward direction into the prostate tissue uponadvancement of the carrier.
 49. A catheter as defined in claim 48wherein: the inclined member comprises an inclined surface positioned onthe exterior of the catheter.
 50. A catheter as defined in claim 48wherein: the inclined member comprises a peg having an inclined surfacepositioned within the channel.
 51. A catheter as defined in claim 40further comprising: an opening in the catheter located at theterminating distal end of the channel and located at the predeterminedposition spaced proximally from the expandable balloon; and a membranewhich covers the opening and through which the distal end portion of thecarrier penetrates upon advancement of the distal end portion of thecarrier out of the channel and into the prostate tissue.
 52. A catheteras defined in claim 51 wherein: the heating device is positioneddistally of the opening and within the prostate tissue when the catheteris retained relative to the bladder.
 53. A catheter as defined in claim40 wherein: the deflecting element deflects the distal end portion ofthe carrier in the longitudinal direction toward the balloon.
 54. Acatheter as defined in claim 53 wherein: the advancement of the distalend portion of the carrier in the radially outward and longitudinaldirection defines an angle of at least 20 degrees with respect to alongitudinal axis of the catheter.
 55. A catheter as defined in claim 53wherein: the advancement of the distal end portion of the carrier in theradially outward and longitudinal direction defines an angle ofapproximately 30 degrees with respect to a longitudinal axis of thecatheter.
 56. A catheter as defined in claim 40 wherein: the heatingdevice comprises an antenna from which energy is emitted into theprostate tissue.
 57. A catheter as defined in claim 40 wherein: theheating device comprises a receptacle within the catheter for containingheated liquid.
 58. A catheter as defined in claim 40 wherein: theheating device comprises an intermediary device which expands intoabutment against the urethra.
 59. A catheter as defined in claim 40wherein: the distal end portion of the carrier has sufficient stiffnessto advance the distal end portion into the prostate tissue inapproximately the direction of deflection initiated by the deflectingelement.
 60. A catheter as defined in claim 40 further comprising: anopening in the catheter located at the terminating distal end of thechannel and located at the predetermined position spaced proximally fromthe expandable balloon; and a stiffener element connected to thecatheter adjacent to the opening, the stiffener element reinforcing thecatheter against bending at a position adjacent the opening uponadvancement of the distal end portion of the carrier out of the opening.61. A catheter as defined in claim 20 wherein: the stiffener element ispositioned exteriorly on the catheter.
 62. A catheter as defined inclaim 20 wherein: the stiffener element is positioned interiorly withinthe catheter.
 63. A catheter as defined in claim 36 wherein: the distalend portion of the carrier has sufficient stiffness to continue topenetrate into the prostate tissue in substantially the directioninitiated by the deflecting element upon advancement of the carrier. 64.A catheter as defined in claim 36 wherein: the advancement force is alongitudinal push force applied to the carrier exteriorly of the body.65. A method of monitoring heat treatment of prostate tissue of a livingbody, the prostate tissue surrounding a urethra that extends from adistal bladder to a proximal exterior of the body, the methodcomprising: extending a catheter into the urethra from the exterior ofthe body into the bladder; advancing a carrier proximally through thecatheter from the exterior of the body by applying advancement force tothe carrier at the exterior of the body; penetrating the distal endportion of the carrier out of the catheter and into the prostate tissueto a desired depth in a direction radially outward relative the catheterby advancing the carrier; and separately sensing temperatures of theprostate tissue at a plurality of different radially outward spacedlocations relative to the urethra after the distal end portion of thecarrier has penetrated into the prostate tissue to the desired depth.66. A method as defined in claim 65 further comprising: using separatetemperature sensors positioned at spaced apart positions along thedistal end portion of the carrier to sense each of the plurality oftemperatures by a separate temperature sensor.
 67. A method as definedin claim 65 further comprising: sensing a first temperature of theprostate tissue at a relatively greater radial outward location afterthe distal end portion of the carrier has penetrated into the prostatetissue to the desired depth; and sensing a second temperature of theprostate tissue at a relatively lesser radial outward location after thedistal end portion of the carrier has penetrated into the prostatetissue to the desired depth.
 68. A method as defined in claim 67 furthercomprising: sensing a third temperature of the prostate tissue at arelatively intermediate location after the distal end portion of thecarrier has penetrated into the prostate tissue to the desired depth,the intermediate location existing between the locations where the firstand second temperatures are sensed.
 69. A method as defined in claim 65further comprising: heating the prostate tissue in an area of heattreatment surrounding the urethra; and sensing the plurality oftemperatures of the prostate tissue within the area of heat treatment.70. A method as defined in claim 69 further comprising: penetrating thedistal end portion of the carrier into the prostate tissue at aperiphery of the area of heat treatment as well as within the area ofheat treatment; sensing the plurality of temperatures of the prostatetissue within the area of heat treatment; and additionally sensing thetemperature of the prostate tissue at the periphery of the area of heattreatment.
 71. A method as defined in claim 70 further comprising:sensing the temperature outside of the periphery of the area of heattreatment.
 72. A method as defined in claim 69 further comprising:penetrating the prostate tissue with the distal end portion of thecarrier in a longitudinal direction as well as the radially outwarddirection relative to the urethra; and sensing the plurality oftemperatures at a plurality of different radially spaced andlongitudinally separated locations within the area of heat treatment.73. A method as defined in claim 72 further comprising: penetrating theprostate tissue with the distal end portion of the carrier in thelongitudinal direction toward the bladder.
 74. A method as defined inclaim 73 further comprising: penetrating the prostate tissue with thedistal end portion of the carrier at an angle of at least 20 degreesrelative to the catheter.
 75. A method as defined in claim 73 furthercomprising: penetrating the prostate tissue with the distal end portionof the carrier at an angle of approximately 30 degrees relative to thecatheter.
 76. A method as defined in claim 69 further comprising:emitting energy from an antenna within the catheter to heat the prostatetissue within the area of heat treatment.
 77. A method as defined inclaim 69 further comprising: conducting heat from a heated liquid withinthe catheter to heat the prostate tissue in the area of heat treatment.78. A method as defined in claim 69 further comprising: heating theprostate tissue within the area of heat treatment by delivering energyfrom a heating device positioned within the catheter.
 79. A method asdefined in claim 69 further comprising: expanding an intermediary deviceinto abutment against the urethra while heating the prostate tissue inthe area of heat treatment.
 80. A method as defined in claim 65 furthercomprising: pushing the carrier longitudinally at the exterior of thebody to accomplish advancing the carrier and penetrating the distal endportion of the carrier into the prostate tissue.
 81. A method as definedin claim 65 further comprising: retaining the catheter in the urethrarelative to the bladder by expanding a balloon at the distal end of thecatheter within the bladder and by penetrating the prostate tissue withthe distal end portion of the carrier in the longitudinal directiontoward the bladder.
 82. A method as defined in claim 65 furthercomprising: continuing the penetration of the distal end portion of thecarrier into the prostate tissue in substantially the directioninitiated upon advancing the carrier by utilizing substantially only aninherent stiffness characteristic of the distal end portion of thecarrier.